A260008 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000101 00010101 or 01010101.

36, 49, 109, 209, 436, 828, 1744, 3344, 7005, 13424, 28067, 53992, 112602, 216997, 451535, 872258, 1811173, 3505729, 7264641, 14089470, 29141208, 56621872, 116900698, 227536583, 468975418, 914316503, 1881490568, 3673849908

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-2) + 7*a(n-4) + a(n-5) + 2*a(n-6) + a(n-7) - a(n-8) + a(n-9) for n>10.

Empirical g.f.: x*(36 + 49*x + 37*x^2 + 111*x^3 - 34*x^4 + 31*x^5 - 12*x^6 - 18*x^7 + 25*x^8 - 10*x^9) / (1 - 2*x^2 - 7*x^4 - x^5 - 2*x^6 - x^7 + x^8 - x^9). - Colin Barker, Dec 27 2018

Example

Some solutions for n=4:
..1..0..1....0..1..0....0..0..1....0..0..0....0..0..0....0..0..0....1..0..1
..0..1..0....1..0..1....0..1..0....0..0..1....0..0..0....0..0..1....0..1..0
..1..0..1....0..1..0....1..0..1....0..1..0....1..0..1....0..1..0....1..0..1
..0..1..0....0..0..1....0..1..0....0..0..1....0..1..0....0..0..1....0..0..0
..1..0..1....0..0..0....0..0..1....0..0..0....1..0..1....0..1..0....0..0..1
..0..0..0....1..0..1....0..1..0....0..0..1....0..0..0....1..0..1....0..1..0

Crossrefs

Column 1 of A260015.

Sequence in context: A260015 A374936 A163244 * A261292 A335249 A332287

Adjacent sequences: A260005 A260006 A260007 * A260009 A260010 A260011

Keyword

nonn

Author

R. H. Hardin, Jul 13 2015

Status

approved